I bought these for a bass guitar and found they were quite easy to install and use, I got the locks put on the strap in a matter of seconds and had one strap button on the end of the bass near the bridge, when I tried to screw the other strap button on the horn of the bass the head of the screw became soft and the screwdriver started to lose grip of the screw, I removed it and plan to get another set of straplocks just for the screws, a great product but I wish dunlop provided spare screws (just in case)!